Compounds having an optionally substituted pyridiniomethyl group at the 3-position of the cephem ring have been disclosed in patent applications such as Japanese Patent Publication (KOKAI) 60-237090 (WO 8505106, EP 160969A2), Japanese Patent Publication (KOKOKU) 1-44190 and also Japanese Patent Publication (KOKOKU) 6-70068 (EP 64740B1, U.S. Pat. No. 5,071,979), Japanese Patent Publication (KOKOKU) 2-44476 (EP 159011B1, U.S. Pat. No. 4,833,242), etc. However, there have not been reported compounds wherein a pyridinium ring is substituted with a heterocyclic group having a substituent of the formula --CONHCN or its analogues.
Although a huge number of antibiotics have been marketed so far, the development and characterization of compounds with higher antibiotic activity have been continuously demanded so as to cope with the appearance of multiple drug resistant bacteria and to provide for the diversification of therapy forms. In particular, it has been demanded to develop cephem compounds of broad spectrum which show a long blood half-life and have an excellent in vivo dynamics such as transfer to a tissue.